/*
 * Copyright 2002-2012 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.beans.factory.config;

import org.springframework.beans.BeansException;

/**
 * Allows for custom modification of an application context's bean definitions,
 * adapting the bean property values of the context's underlying bean factory.
 *
 * <p>Application contexts can auto-detect BeanFactoryPostProcessor beans in
 * their bean definitions and apply them before any other beans get created.
 *
 * <p>Useful for custom config files targeted at system administrators that
 * override bean properties configured in the application context.
 *
 * <p>See PropertyResourceConfigurer and its concrete implementations
 * for out-of-the-box solutions that address such configuration needs.
 *
 * <p>A BeanFactoryPostProcessor may interact with and modify bean
 * definitions, but never bean instances. Doing so may cause premature bean
 * instantiation, violating the container and causing unintended side-effects.
 * If bean instance interaction is required, consider implementing
 * {@link BeanPostProcessor} instead.
 *
 * @author Juergen Hoeller
 * @see BeanPostProcessor
 * @see PropertyResourceConfigurer
 * @since 06.07.2003
 */

/**
 * BeanFactory的后置处理类, 我们可以在BeanFactory初始化之后做一些操作.
 * 它提供了个postProcessBeanFactory()方法, 这个方法被调用的时候,
 * 所有的BeanDefinition已经被创建, 但是还没有被初始化(实例化). 也就是说, 通过它我们可以在初始化任何Bean之前,
 * 做各种操作, 甚至读取并修改BeanDefinition(bean定义的元数据).
 *
 * 允许自定义修改应用程序上下文的bean定义，
 * 调整上下文的底层bean工厂的bean属性值。
 */
public interface BeanFactoryPostProcessor {

    /**
     * Modify the application context's internal bean factory after its standard
     * initialization. All bean definitions will have been loaded, but no beans
     * will have been instantiated yet. This allows for overriding or adding
     * properties even to eager-initializing beans.
     * <p>
     * 修改应用程序上下文的内部bean工厂的标准
     * 初始化。 所有bean定义都已加载，但没有bean
     * 将被实例化。 这允许覆盖或添加
     * 属性甚至是预初始化bean。
     *
     * @param beanFactory the bean factory used by the application context
     * @throws org.springframework.beans.BeansException in case of errors
     */
    void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory) throws BeansException;

}
